1. Technical Field
The present disclosure relates to an image scanning apparatus configured such that a skew phenomenon, or oblique proceeding of a sheet conveyed therein is suppressed.
2. Conventional Art
Conventionally, there has been known an image scanning apparatus which is configured such that oblique proceeding of a sheet conveyed inside the apparatus is prevented or suppressed. Such a conventional scanning apparatus generally has, for example, a housing, a first guide part, a second guide part, a scanning unit and a sheet conveying unit. For example, the housing has a first inlet opening, a second inlet opening and an outlet. The second inlet opening is located next to the first inlet opening in a width direction thereof, a width of the second inlet opening being smaller than that of the first inlet opening. The outlet communicates with the first and second inlet openings. The first guide part is provided to the housing. The first guide part connects the first inlet opening with the outlet, and has a curved part. The second guide part is also provided to the housing. The second guide part linearly connects the second inlet opening with a confluence position which is located in the vicinity of the curved part of the first guide part. The scanning unit is provided inside the housing. The conveying unit is provided inside the housing.
The second guide part has a second guide surface. The second guide surface extends from the second inlet opening to the confluence position, and configured to contact a medium (e.g., a card) introduced from the second inlet opening from below. The first guide part has a first lower guide surface and a first upper guide surface. The first lower guide surface is connected to the second guide surface at the confluence position. The first lower guide surface located on the downstream with respect to the confluence position extends in a direction substantially similar to a direction where the second guide surface extends, and is configured to contact the medium passing the confluence position from below. The first upper guide surface faces the first lower guide surface. The conveying unit has a first conveying part. The first conveying part has a driving roller and the driven roller. The driving roller is provided on the first lower guide surface side at the first guide part, and inside a path extending from the second inlet opening to the outlet in the width direction. The driving roller is configured to rotate about a driving shaft (rotation shaft) which is located on the outlet side with respect to the confluence position. The driven roller is arranged on the first upper surface side at the first guide part. The driven roller is rotatably supported about a driven shaft (another rotation shaft) which is located above the driving axis of the driving roller, or above a plane extending in a direction from the confluence position to the outlet (i.e., in a sheet conveying direction). The driven roller inside a path extending from the second inlet opening to the outlet in the width direction is spaced from the driving roller by a predetermined amount.
In such a conventional image scanning apparatus, the conveying unit conveys the medium guided by the first guide part and the second guide part to the outlet. The scanning unit scans an image formed on the medium which has passed the confluence position. At this stage, the first conveying unit conveys the medium introduced from the second inlet opening to the outlet via the confluence position. On the other hand, the first conveying unit is configured such that the driven axis of the driven roller is located above the driving axis of the driving roller, and the driven roller is spaced from the driving roller by the predetermined amount, thereby a relatively wide medium introduced from the first inlet opening is not sandwiched by the driving roller and the driven roller.